#include <stdio.h>
#include <string.h>

int my_add(int a, int b){
	return a+b;
}

int my_sub(int a, int b){
	return a-b;
}

struct Student{
	int id;
	char name[32];
	char gender;
	int (*p)(int, int);
};

int main(int argc, const char *argv[])
{
	struct Student s;
	s.p = my_add;
	printf("%d\n", s.p(10, 20)); // 30
	s.p = my_sub;
	printf("%d\n", s.p(10, 20)); // -10

	return 0;
}
